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Soft Beaters

Syntronics Percussion Module (CBM64)

Sampled drum sounds on the CBM 64

If I had a Commodore 64 and somebody told me I cold turn it into a decent quality digital drum machine for just £65, my ears would prick up fast enough to set my hair on fire. This is in fact what happened a few weeks ago (hyperbole aside) when I encountered the Syntron module, a little black box which plugs into the 64's User port and which has a single jack socket for Audio Out and a phono socket for Trigger Out.

Inside is a simple circuit with just a dozen discrete components and two carefully-scrubbed chips. The Syntron is in fact just a little digital-analogue convertor, and its heart is really the software which comes in the form of a single floppy disk. The Commodore's 1541 disk drive is notoriously slow, but even so the one-minute-plus loading time for the disk is a bit excessive. It does mean that you've got all the operational software, the sounds themselves and a set of demo patterns loaded though.


The first screen display is a menu with five options; Program Rhythm Line, Rhythm Track Composition, Set Tempo, Load Rhythms and Rhythm Track, and Save Rhythms and Rhythm Track. The first of these, Program Rhythm Line (P) calls up a display of a single pattern which can be up to 38 beats long. At the top left is a note of the Rhythm Number - you can program ten rhythms and recall them with the computer's keys 0-9. The Tempo is displayed on the top right (that's dealt with in a later option) and the seven available instruments are listed down the right hand edge. These are labelled C (Crash Cymbal) O (Open Hi-Hat) H (Closed Hi-Hat) D (Drum (small tom)), S (Snare) and G (Grand Tom). This labelling is a bit unusual, but programming isn't by any means difficult. The cursor keys manoeuvre a pointer to the required beat, and tapping the appropriate keys writes in the sound on that beat.

The Menu Screen

Some symbols you never knew the 64 possessed are used to indicate when a sound is in place, and F1 marks the end of the bar with a solid white line. When you've completed a pattern you can play it by hitting F7; you can't make it loop unless you write it into a chain (Track), and it's also impossible to play the sounds "live" by just hitting the appropriate keys. Still, you can't have everything.


Rhythm Track Composition is as easy as falling off a log. The Page R-style display produces five columns into which you simply enter, for instance, Pattern 2x4, Pattern 0x2, Pattern 7x1, and so on. When you've completed the track, press F7 to play the track once or F5 to loop it — there's a slight pause between track repeats when looping but you may be able to program this out, say with one 31-beat rhythm. But since the maximum length of a track is something like 115 32-beat patterns you'll probably find that you can write a track long enough for most songs without wanting to repeat it.

Around this point the Syntron software starts to show its underwear a little. Once you start a Track playing it's very difficult to stop it - you have to struggle with the Run-Stop/Restore buttons to break the program, and then re-run it from the menu. You haven't lost any information and in fact it doesn't take that long - it's just a bit frightening to do it.

Composition Page

The Tempo page simply allows you to type in a new speed from 0, exceedingly slow, to 64, much faster than you'd ever need. L allows you to load rhythms from disk; as you do so a complete rhythm track is loaded up too, and the main disk includes a demo set which you can load from the L page by typing "DEMO *".

If you use the load function in the middle of programming a Track, you can call up more than your original ten different patterns, so that's not a limitation. Disk access is reasonably fast, as it is in the S (Save) mode which lets you store your current ten rhythms and single track under a title of your own choosing. There seems to be no way to get a disk directory other than by breaking the program and using Commodore BASIC, but the small handbook I had wasn't comprehensive - both it and the disk content are being slightly updated before release.


Since Syntron is software-driven, updates are possible, and an optional disk with seven new sounds including Clap and Syntom will be available. In the existing set you can load a low instead of a high-pitched snare, and overall the sounds are astonishingly good: the best comparison would be the Korg DDM110; it has the same slightly clipped but very high-quality effects, and the bass and snare are excellent. The hi-hats are good, the Ride cymbal decent but the Crash predictably a little truncated; the toms are horrible though, short and bendy, so roll on the alternative sounds.

Other points; not much chance of adding individual audio outputs, or of interfacing to complex equipment without some further convertor unit. The trigger out is a simple one pulse per beat, perfect for the EDP Spider sequence but needing a good deal of thought to drive DIN Sync or MIDI-based equipment.

Background noise is very low while the drums are playing, fractionally higher when stopped but nothing which couldn't be dealt with by a little EQ or gating. The Syntron is well up to recording quality, and so has to be recommended to anybody who already has a 64. It could even be a good argument in favour of the 64 is you're still thinking of buying a micro, but the imminent Spectrum version of the Syntron is apparently much more powerful and easily interfaceable.

Contact: Vince Hill Associates, (Contact Details).

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Electronic Soundmaker & Computer Music - Copyright: Cover Publications Ltd, Northern & Shell Ltd.


Electronic Soundmaker - Sep 1985

Donated & scanned by: Chris Strellis

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